Nerve growth factor (NGF), which is found in particular abundance in the hippocampus and cerebral cortex of the brain, is a neurotrophic factor which is required by a living body for sustaining life and functions and stimulates differentiation and growth of neurons. In the brain, NGF acts on cholinergic neurons. Alzheimer's disease is accepted to exhibit a primary lesion of regeneration and falling of cholinergic neurons, and on the basis of this understanding, NGF has been administered to the brain as therapy for the disease.
However, NGF, being a protein having a molecular weight of 12,000, cannot pass through the blood-brain barrier, and thus does not serve as practical means for the treatment of Alzheimer's disease.
Meanwhile, cyclohexenone long-chain alcohol has a low molecular weight and is known to be useful as a prophylactic or therapeutic drug for cerebral diseases such as dementia, in view that, when administered orally, the alcohol reaches the brain, passes through the blood-brain barrier, and at low concentration exhibits excellent effect to stimulate growth of neurons, to thereby directly act on neurites to elicit extension (Japanese Kohyo (PCT) Patent Publication No. 2001-515058).
Hitherto, cyclohexenone long-chain alcohol has been produced through a complicated process; for example, by reacting cyclohexanone or methyl-substituted 2-cyclohexen-1-one with benzenesulfinate in the presence of acid, then with ethylene glycol to form a ketal compound, and further with ω-halogenoalcanol, followed by treatment with an acid to remove a protective group. Specifically, in the case of production of 3-(14-hydroxytetradecyl)-4-methyl-2-cyclohexen-1-one from a starting material 3-methylcyclohexenone, seven reaction steps have conventionally been required.